feat: update install-hook to add SessionEnd analysis hook

[melagiri]

Context

Part of the Native Analysis via Claude Code Hooks feature (Phase 12, v4.8.0).
Plan: docs/plans/2026-03-28-native-analysis-hooks.md

Issue 4 of 6 — Depends on #240 (insights command must exist).

Problem

Today code-insights install-hook only installs a Stop hook for auto-sync. To enable native analysis, we also need a SessionEnd hook that triggers code-insights insights --hook --native -q.

Solution

Update installHookCommand() to install both hooks by default:

{
  "hooks": {
    "Stop": [
      { "hooks": [{ "type": "command", "command": "node <cli> sync -q" }] }
    ],
    "SessionEnd": [
      { "hooks": [{ "type": "command", "command": "node <cli> insights --hook --native -q", "timeout": 120000 }] }
    ]
  }
}

New Flags

• --sync-only — install only the Stop (sync) hook
• --analysis-only — install only the SessionEnd (analysis) hook

Updated Uninstall

uninstallHookCommand() cleans both Stop and SessionEnd hooks.

Updated Messaging

Install Code Insights Hooks

This will add two Claude Code hooks:

  Stop hook         — Syncs sessions after each response
  SessionEnd hook   — Analyzes sessions using your Claude subscription
                      No API key needed. (~15-30s per session)

Install both hooks? [Y/n]

Acceptance Criteria

• Default install-hook installs both Stop + SessionEnd hooks
• --sync-only installs only Stop hook
• --analysis-only installs only SessionEnd hook
• Duplicate detection works for both hook types
• uninstall-hook removes both hook types
• SessionEnd hook has 120s timeout configured
• Updated CLI output messaging explains both hooks
• Telemetry tracks which hook types were installed

[melagiri]

PM Handoff — Issue 4 of 6 (Phase 12)

Worktree: /Users/melagiri/Workspace/codeInsights/code-insights-install-hook-sessionend/
Branch: feature/install-hook-sessionend

---

CRITICAL: Verify SessionEnd Hook Event Name First

The plan doc references SessionEnd as the hook event name, but Context7 research found the Claude Code docs do not explicitly list SessionEnd as a valid hook event. The documented events are: PreToolUse, PostToolUse, Stop, SessionStart, UserPromptSubmit, SubagentStop.

Dev must verify before implementing:

• Run claude --help or check ~/.claude/settings.json to confirm valid hook event names
• If SessionEnd doesn't exist, the Stop event (fires when Claude finishes responding) may be the right event for analysis — it already fires at logical session end and stdin already carries { session_id, transcript_path }
• The insights --hook command already handles stdin JSON correctly regardless of which event fires it
• Update the implementation to use whatever event name actually works

---

File Pointers

File	Change
cli/src/commands/install-hook.ts	Primary — add SessionEnd hook, --sync-only/--analysis-only flags, update uninstall
cli/src/commands/__tests__/install-hook.test.ts	New — TDD, write tests first
cli/src/index.ts	Minor — update command description, add --sync-only/--analysis-only option registration

---

Current Hook Structure (install-hook.ts)

The current file installs only a Stop hook at settings.hooks.Stop[]. Key details:

• HOOKS_FILE = ~/.claude/settings.json
• Duplicate detection: checks if any hook command includes 'code-insights'
• HookConfig interface: { matcher?: string; hooks: Array<string | { type, command, timeout? }> }
• getHookCommand() helper handles both string and object hook formats
• Telemetry: trackEvent('cli_install_hook', { success: true/false })

---

Plan Doc Section 7 (LLD)

docs/plans/2026-03-28-native-analysis-hooks.md section 7 shows the target structure:

// Existing Stop hook (sync)
const stopHook: HookConfig = {
  hooks: [{ type: 'command', command: `node ${cliPath} sync -q` }],
};

// New SessionEnd hook (analysis)
const sessionEndHook: HookConfig = {
  hooks: [{
    type: 'command',
    command: `node ${cliPath} insights --hook --native -q`,
    timeout: 120000,  // 2 minutes
  }],
};

---

Acceptance Criteria (from Issue #241)

• Default install-hook installs both Stop + SessionEnd hooks
• --sync-only installs only Stop hook
• --analysis-only installs only SessionEnd hook
• Duplicate detection works for both hook types
• uninstall-hook removes both hook types
• SessionEnd hook has 120s timeout configured
• Updated CLI output messaging explains both hooks
• Telemetry tracks which hook types were installed

---

TDD Required

Tests go in cli/src/commands/__tests__/install-hook.test.ts (file does not exist yet — create it).

Write tests before implementation. Key scenarios to cover:

• Default install writes both hooks to settings.json
• --sync-only writes only Stop hook
• --analysis-only writes only SessionEnd hook
• Duplicate detection fires for each hook type independently
• Uninstall removes both hook types, cleans empty arrays
• Settings file with pre-existing (non-code-insights) hooks is preserved

---

Telemetry Update

Extend the existing trackEvent('cli_install_hook', ...) call to include which hooks were installed:

trackEvent('cli_install_hook', { success: true, sync_hook: true, analysis_hook: true })

[melagiri]

Completed — PR #250 Ready for Merge

All acceptance criteria satisfied. Triple-layer review complete, review feedback addressed.

PR: #250
Tests: 16 new tests, 546 total passing
Build: pnpm build passes, zero errors